Mitsubishi MELSEC-A Series Reference Manual page 261

9. PROGRAMMING
Device
Name
Number
Loopback
D9205
execution station
Loopback
D9206
execution station
D9207
D9208 Link scan time
D9209
D9210 Retry count
Loop switching
D9211
count
Table 9.5 List of MELSECNET special link registers (Continued)
Data
Station executing forward
loopback
Station executing reverse
loopback
Maximum value
Minimum value
Current value
Total number stored
Total number stored
• Stores the number of local station or remote I/O station at which
loopback is being executed.
Example: "1" is stored in D9205 and "3" is stored in D9206.
• The values stored in D9205 and D9206 are not reset to "0" when
the data link returns to the normal state (data link in forward
loop).
• Reset the programmable controller CPU to return the set values
to "0".
• Stores the time used for data link processing (link scan time) by
all of the local stations and remote I/O stations in the loop
currently being used for data link. (in 10ms unit)
• Link scan time definition:
• Stores the total number of retries conducted when a transmission
error occurs.
• Definition of retry processing:
If data is lost or becomes unreliable due to the occurrence of a
data transmission processing error, the same data is sent again.
• Counting stops if the number of retries exceeds the maximum
limit "FFFF ".
H
• Execute reset operation to clear the data to "0".
• Stores the total number of times that the forward loop is switched
to a reverse loop or to loopback.
• Counting stops if the number of switches exceeds the maximum
limit "FFFF ".
H
• Execute reset operation to clear the data to "0".
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Description